The invention relates to a dual clutch transmission that can be shifted into several driving gears, comprising a first input shaft, a second input shaft, and first, second and third drive shafts.
Such a dual clutch transmission is known from the publication WO 2006/128626. The three drive shafts are connected such as to co-rotate with an output that is designed as a differential transmission. A gear wheel connection is allocated to each driving wheel, the gear wheel connection comprising a loose wheel and a fixed wheel, wherein the loose wheel can be connected by the respective gear wheel connections via the gear shifting clutch in a fixed manner with the shaft for co-rotating therewith, on which shaft the loose wheel is carried. When a fixed connection is established via the gear shifting clutch between the loose wheel and the shaft, the respective driving gear is engaged so that torque can be transmitted between one of the input shafts and the output.
In the WO 2006/128626 a dual clutch transmission comprising a stepped gear is disclosed comprising a first gear wheel and a second gear wheel. The step wheel can be connected via a gear shifting clutch with the drive shaft carrying the step wheel. The first gear wheel is engaged by a loose wheel allocated to a reverse driving gear, this loose wheel being carried on another drive shaft. The second gear wheel of the step wheel is engaged with a fixed wheel that is carried on one of the input shafts. In case of the step wheel having been shifted into gear, i.e. when a fixed connection is established between the step wheel and the drive shaft so that these two co-rotate, a second forward driving gear of the dual clutch transmission is engaged. For engaging the reverse driving gear, it is necessary to establish a fixed connection between the loose wheel of the reverse driving gear and a respective drive shaft so that these co-rotate. When the reverse driving gear is engaged, it has to be guaranteed that the step wheel is no longer connected in a rotationally fixed manner with the drive shaft carrying the step wheel. In this case, the step wheel functions as an intermediate gear wheel for reversing the rotational direction for establishing the reverse driving gear, but does not transmit a torque into the drive shaft of the step wheel.
Even though a low axial dimension can be achieved by the dual clutch transmission according to WO 2006/128626, there is a need for additional dual clutch transmissions that accomplish a short axial length. The structure should be as simple as possible, while at the same time allowing many degrees of freedom for providing various transmission ratios of the individual driving gears.